| Partial eclipse | |||||||||||||
 The Moon's hourly motion shown right to left | |||||||||||||
| Date | August 27, 1988 | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Gamma | −0.8682 | ||||||||||||
| Magnitude | 0.2916 | ||||||||||||
| Saros cycle | 118 (50 of 74) | ||||||||||||
| Partiality | 112 minutes, 58 seconds | ||||||||||||
| Penumbral | 262 minutes, 33 seconds | ||||||||||||
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A partiallunar eclipse occurred at the Moon’sascending node of orbit on Saturday, August 27, 1988,[1] with an umbralmagnitude of 0.2916. A lunar eclipse occurs when theMoon moves into theEarth's shadow, causing the Moon to be darkened. A partial lunar eclipse occurs when one part of the Moon is in the Earth's umbra, while the other part is in the Earth's penumbra. Unlike asolar eclipse, which can only be viewed from a relatively small area of the world, a lunar eclipse may be viewed from anywhere on thenight side of Earth. Occurring only about 7 hours beforeperigee (on August 17, 1988, at 17:50 UTC), the Moon's apparent diameter was larger.[2]
The eclipse was completely visible over easternAustralia, westernNorth America, and much of thePacific Ocean, seen rising over western Australia and the eastern half ofAsia and setting over much of North America andSouth America.[3]
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Shown below is a table displaying details about this particular solar eclipse. It describes various parameters pertaining to this eclipse.[4]
| Parameter | Value |
|---|---|
| Penumbral Magnitude | 1.23803 |
| Umbral Magnitude | 0.29159 |
| Gamma | −0.86816 |
| Sun Right Ascension | 10h25m02.1s |
| Sun Declination | +09°54'10.9" |
| Sun Semi-Diameter | 15'50.0" |
| Sun Equatorial Horizontal Parallax | 08.7" |
| Moon Right Ascension | 22h26m40.4s |
| Moon Declination | -10°41'41.3" |
| Moon Semi-Diameter | 16'43.7" |
| Moon Equatorial Horizontal Parallax | 1°01'23.7" |
| ΔT | 56.1 s |
This eclipse is part of aneclipse season, a period, roughly every six months, when eclipses occur. Only two (or occasionally three) eclipse seasons occur each year, and each season lasts about 35 days and repeats just short of six months (173 days) later; thus two full eclipse seasons always occur each year. Either two or three eclipses happen each eclipse season. In the sequence below, each eclipse is separated by afortnight.
| August 27 Ascending node (full moon) | September 11 Descending node (new moon) |
|---|---|
|  |
| Partial lunar eclipse Lunar Saros 118 | Annular solar eclipse Solar Saros 144 |
This eclipse is a member of asemester series. An eclipse in a semester series of lunar eclipses repeats approximately every 177 days and 4 hours (a semester) at alternatingnodes of the Moon's orbit.[5]
The lunar eclipses onJune 27, 1991 (penumbral) andDecember 21, 1991 (partial) occur in the next lunar year eclipse set.
| Lunar eclipse series sets from 1988 to 1991 | ||||||||
|---|---|---|---|---|---|---|---|---|
| Descending node | Ascending node | |||||||
| Saros | Date Viewing | Type Chart | Gamma | Saros | Date Viewing | Type Chart | Gamma | |
| 113 | 1988 Mar 03 | Penumbral | 0.9886 | 118 | 1988 Aug 27 | Partial | −0.8682 | |
| 123 | 1989 Feb 20 | Total | 0.2935 | 128 | 1989 Aug 17 | Total | −0.1491 | |
| 133 | 1990 Feb 09 | Total | −0.4148 | 138 | 1990 Aug 06 | Partial | 0.6374 | |
| 143 | 1991 Jan 30 | Penumbral | −1.0752 | 148 | 1991 Jul 26 | Penumbral | 1.4370 | |
TheMetonic cycle repeats nearly exactly every 19 years and represents aSaros cycle plus one lunar year. Because it occurs on the same calendar date, the Earth's shadow will be in nearly the same location relative to the background stars.
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This eclipse is a part ofSaros series 118, repeating every 18 years, 11 days, and containing 73 events. The series started with a penumbral lunar eclipse on March 2, 1105. It contains partial eclipses from June 8, 1267 through August 12, 1375; total eclipses from August 22, 1393 through June 22, 1880; and a second set of partial eclipses from July 3, 1898 throughSeptember 18, 2024. The series ends at member 73 as a penumbral eclipse on May 7, 2403.
The longest duration of totality was produced by member 37 at 99 minutes, 22 seconds on April 7, 1754. All eclipses in this series occur at the Moon’sascending node of orbit.[6]
| Greatest | First | |||
|---|---|---|---|---|
| The greatest eclipse of the series occurred on1754 Apr 07, lasting 99 minutes, 22 seconds.[7] | Penumbral | Partial | Total | Central |
| 1105 Mar 02 | 1267 Jun 08 | 1393 Aug 22 | 1465 Oct 04 | |
| Last | ||||
| Central | Total | Partial | Penumbral | |
| 1826 May 21 | 1880 Jun 22 | 2024 Sep 18 | 2403 May 07 | |
Eclipses are tabulated in three columns; every third eclipse in the same column is oneexeligmos apart, so they all cast shadows over approximately the same parts of the Earth.
| Series members 40–61 occur between 1801 and 2200: | |||||
|---|---|---|---|---|---|
| 40 | 41 | 42 | |||
| 1808 May 10 | 1826 May 21 | 1844 May 31 | |||
| 43 | 44 | 45 | |||
| 1862 Jun 12 | 1880 Jun 22 | 1898 Jul 03 | |||
| 46 | 47 | 48 | |||
| 1916 Jul 15 | 1934 Jul 26 | 1952 Aug 05 | |||
 |  |  |  |  |  |
| 49 | 50 | 51 | |||
| 1970 Aug 17 | 1988 Aug 27 | 2006 Sep 07 | |||
 |  | | |  |  |
| 52 | 53 | 54 | |||
| 2024 Sep 18 | 2042 Sep 29 | 2060 Oct 09 | |||
|  |  |  | ||
| 55 | 56 | 57 | |||
| 2078 Oct 21 | 2096 Oct 31 | 2114 Nov 12 | |||
| 58 | 59 | 60 | |||
| 2132 Nov 23 | 2150 Dec 04 | 2168 Dec 14 | |||
| 61 | |||||
| 2186 Dec 26 | |||||
This eclipse is a part of atritos cycle, repeating at alternating nodes every 135synodic months (≈ 3986.63 days, or 11 years minus 1 month). Their appearance and longitude are irregular due to a lack of synchronization with theanomalistic month (period of perigee), but groupings of 3 tritos cycles (≈ 33 years minus 3 months) come close (≈ 434.044 anomalistic months), so eclipses are similar in these groupings.
| Series members between 1801 and 2200 | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| 1803 Feb 06 (Saros 101) | 1814 Jan 06 (Saros 102) | 1824 Dec 06 (Saros 103) | 1846 Oct 04 (Saros 105) | ||||||
| 1857 Sep 04 (Saros 106) | 1868 Aug 03 (Saros 107) | 1879 Jul 03 (Saros 108) | 1890 Jun 03 (Saros 109) | 1901 May 03 (Saros 110) | |||||
 |  | ||||||||
| 1912 Apr 01 (Saros 111) | 1923 Mar 03 (Saros 112) | 1934 Jan 30 (Saros 113) | 1944 Dec 29 (Saros 114) | 1955 Nov 29 (Saros 115) | |||||
 |  |  |  |  |  |  |  |  |  |
| 1966 Oct 29 (Saros 116) | 1977 Sep 27 (Saros 117) | 1988 Aug 27 (Saros 118) | 1999 Jul 28 (Saros 119) | 2010 Jun 26 (Saros 120) | |||||
 |  |  |  | | |  |  |  |  |
| 2021 May 26 (Saros 121) | 2032 Apr 25 (Saros 122) | 2043 Mar 25 (Saros 123) | 2054 Feb 22 (Saros 124) | 2065 Jan 22 (Saros 125) | |||||
 |  |  |  |  |  |  |  | ||
| 2075 Dec 22 (Saros 126) | 2086 Nov 20 (Saros 127) | 2097 Oct 21 (Saros 128) | 2108 Sep 20 (Saros 129) | 2119 Aug 20 (Saros 130) | |||||
| 2130 Jul 21 (Saros 131) | 2141 Jun 19 (Saros 132) | 2152 May 18 (Saros 133) | 2163 Apr 19 (Saros 134) | 2174 Mar 18 (Saros 135) | |||||
| 2185 Feb 14 (Saros 136) | 2196 Jan 15 (Saros 137) | ||||||||
This eclipse is a part of the long periodinex cycle, repeating at alternating nodes, every 358synodic months (≈ 10,571.95 days, or 29 years minus 20 days). Their appearance and longitude are irregular due to a lack of synchronization with theanomalistic month (period of perigee). However, groupings of 3 inex cycles (≈ 87 years minus 2 months) comes close (≈ 1,151.02 anomalistic months), so eclipses are similar in these groupings.
| Series members between 1801 and 2200 | |||||
|---|---|---|---|---|---|
| 1814 Dec 26 (Saros 112) | 1843 Dec 07 (Saros 113) | 1872 Nov 15 (Saros 114) | |||
| 1901 Oct 27 (Saros 115) | 1930 Oct 07 (Saros 116) | 1959 Sep 17 (Saros 117) | |||
 |  |  |  |  |  |
| 1988 Aug 27 (Saros 118) | 2017 Aug 07 (Saros 119) | 2046 Jul 18 (Saros 120) | |||
| |  |  |  |  |
| 2075 Jun 28 (Saros 121) | 2104 Jun 08 (Saros 122) | 2133 May 19 (Saros 123) | |||
| 2162 Apr 29 (Saros 124) | 2191 Apr 09 (Saros 125) | ||||
A lunar eclipse will be preceded and followed by solar eclipses by 9 years and 5.5 days (ahalf saros).[8] This lunar eclipse is related to two solar eclipses ofSolar Saros 125.
| August 22, 1979 | September 2, 1997 |
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